To guarantee a more stable data service such as multimedia service in future-generation mobile communication, attention has been increasingly drawn to a hierarchical cell structure or heterogeneous cell structure in which micro cells (or pico cells or femto cells) for low power/near field communication are co-located within a macro cell-based homogeneous network.
FIG. 1 illustrates a network environment having a heterogeneous cell structure.
As shown in FIG. 1, one macro cell includes Macro UEs (MUE) served by a macro eNB (MeNB). Additionally, FIG. 1 shows that pico cells, which are a kind of micro cell, are formed at a boundary region of a macro cell and served by Pico eNBs (PeNBs). UEs served by PeNBs may be represented by Pico UEs (PUEs) to distinguish the UEs from MUEs. The PeNBs, which are an example of eNBs providing services to a micro cell or small cell, may correspond to small eNBs of various types.
Since installation of additional macro eNBs is inefficient in terms of cost and complexity relative to system performance improvement, the heterogeneous network structure is expected to be further utilized through installation of micro eNBs as described above.
According to a heterogeneous network structure which is under discussion for a communication network, multiple micro cells coexist in one macro cell, and serve corresponding UEs using resources allocated thereto according to a cell coordination scheme, as shown in FIG. 1.